1. Field of the Invention
The present invention relates to dual curing compositions and methods for preparing and using same. The compositions of the present invention cure by exposure to moisture and/or radiation in the electromagnetic spectrum, e.g., ultraviolet (UV) light, to provide flexible polyether or polyester resins.
2. Brief Description of Related Technology
A variety of silicone compositions have been developed that may be used as sealants, conformal coatings, potting compounds, and the like. Among the numerous silicone compositions that have evolved, some depend on atmospheric humidity and/or moisture to be present on the substrate to which the composition is applied, for their cure. Although such moisture-curing silicone systems provide good physical properties and performance when fully cured, they suffer the disadvantage that the moisture curing process is relatively slow.
As a consequence, silicone compositions that depend on other curing processes have been developed which are significantly faster than the moisture-curing process. In particular, photocurable (e.g., UV-curable) silicones have been developed which offer a fast curing speed, far superior to conventional moisture-curing silicone. These silicone compositions may include a photoinitiator that provides a faster and more effective cure. Silicone compositions that are both moisture-curable and photo-curable have also been developed that provide a rapid cure. Examples of these are described in U.S. Pat. No. 5,663,269 to Chu, et al. (Chu); U.S. Pat. No. 6,140,444 to Levandoski, et al. (Levandoski); U.S. Pat. No. 4,528,081 to Lien et al. (Lien) and U.S. Pat. No. 4,699,802 to Nakos et al. (Nakos), all of which are hereby expressly incorporated herein by reference.
The need for dual curing compositions has increased as additional applications in the automotive, structural engineering and electronic industry have been identified. The present invention provides new dual curing resins, which are useful in these and other applications.